Who defines chemsex? Pharmacosexual ecologies, epistemic coloniality and global health governance

Chemsex has become a prominent category through which global health addresses sexuality, drug use, human immunodeficiency virus prevention, harm reduction and queer sexual health. Yet its dominant definitions emerged from Euro-North American sexual, pharmacological, digital and clinical ecologies, particularly in the United Kingdom, where chemsex became linked to crystal methamphetamine, gamma-hydroxybutyrate/gamma-butyrolactone and mephedrone. This article argues that the global circulation of this framework reveals asymmetries in the geopolitics of health knowledge. When applied uncritically to Latin America and other Global South contexts, chemsex may reproduce epistemic coloniality by obscuring local substances, vocabularies, markets, inequalities, healthcare precarities and community practices of care. Drawing on decolonial theory, epistemologies of the South and critiques of epistemic injustice, the article advances pharmacosexual ecologies as a situated alternative to universalising definitions. It repositions Global South contexts as sites of conceptual production and outlines implications for surveillance, harm reduction and drug policy grounded in epistemic justice.